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Cotter and Strap. 243
as above described, until cut right through, when there ought to
be little finishing with file. Drill and tap for set screw in butt
end, return the rod to the lathe for polishing, chip off the
centreing pieces, draw-file, and polish the ends.
The Strap (Fig. 253), being forged fairly to shape, is first
scribed to thickness, and planed. A sheet-iron template is next
provided of the form shewn at N, Fig. 253, which is placed on
the forging and the form traced. Finish the contour with
vertical mill or slotting-tool, clamping the work as at o for the
outer and as at P for the inner tooling. The oil-cup is next
marked off as at Q, and the strap clamped to an angle-plate as at
r< for turning, boring, and drilling. At the same time the screw
is chased for the oil-cup cover. Lastly, line out the cotter hole
as at s, and slot drill by blocking up in .the machine vice as at T,
and, on removal, draw-file and polish.
The Cotter u is first planed to thickness from good steel,
and then marked off to length and width. Both edges are then
planed to the marked lines, and the rest finished very exactly by
file, with the aid of the gauge template v, great care being taken
regarding the thickness.
The Gib w is similarly marked out, and the sloping edge
planed. The channel is then removed with a shaping tool,
several gibs being bolted together for economy, and the rest
finished very carefully with the file.
The Large Brasses are marked off and planed in the same
way as were those for the bearing, Fig. 249, and are then bolted
down very firmly to the boring table as at x, with liners between
to represent the draw of the cotter, and with bolts lying close up
to the outer surfaces. See their faces are set at right angles to
the boring bar, which is inserted as before, and the work traversed
into position. Bore right through, and finish the radii with a
specially ground tool, as at Y.
The Small Brasses are shewn at d and z. They are
planed as before, with the exception of the sloping side, which
requires a new setting, as shewn at e} and is planed with a side
tool. The 'ring' faces must also be left untouched, these being
turned at the same time as the hole is bored, which is done by
bolting the two brasses together, with a wedge between for the